The dangerous Hendra virus has claimed the life of an elderly Australian stock horse in northern New South Wales.

Five people who had contact with the infected horse are being monitored by health authorities.

The case – the first in the state this year – was confirmed after testing on Saturday by the New South Wales Department of Primary Industries. The animal had died on Thursday.

The stock horse, a 31-year-old gelding, was on a property west of Murwillumbah. It is understood the unwell animal was pulled from a dam, but died.

Samples have been taken for testing from five other horses on the property. Authorities now routinely test cats and dogs potentially exposed to the the virus, but none were on the property in question.

The property is said to have regular activity from native fruit bats known as flying foxes, which are known to carry the virus.

Authorities have been urging horse owners to vaccinate their animals against the virus.